Tuesday, May 22, 2007
A lot has been written on energy dependence. I'm convinced that we should be producing energy in as many different ways as it is ecologically feasible to do. There is no method of energy generation/collection that has zero pollution. Although some methods shine brighter than others, many just move the pollution to areas where coyotes don't vote. The electric car isn't much better than a gasoline engine if the electricity is generated by burning coal out in the boonies somewhere. Large hydro-power generation stations in Canada flood large areas of land (e.g. the Lower Churchill Hydro Generation Project flooding 121 square kilometers of land area for 2.8 GigaWatt capacity). There are tradeoffs to everything.
Strengths and Weaknesses
Along with their weaknesses, each method has some strengths.
- Hydro power generation (with dams) allows you to defer energy generation (i.e. store it) until you need it by raising the water level behind the damn. In this sense, it can act like a ginormous battery or capacitor.
- Wind power is fickle. Although many locations can provide necessary windspeed to make them worthwhile, if the wind isn't blowing, there's not a damn thing you can do about it. No power for you! Otherwise, wind power is pretty clean, except for the noise and visual pollution.
- Solar power (electrical), like wind power, only generates electricity while the sun is available. It is a "now or never" type of energy source - if you do not harvest it now, you will never will. As such, any but the smallest photovoltaic operations use a power point tracker to dynamically keep the load at the point of maximum power transfer (or 50% electrical efficiency). Actually, a Heliostat can be used to store solar power in the specific heat capacity of liquid sodium, allowing it to continue to generate electrical power long after the sun has gone down. Both methods require large land area for solar collection. At sea level, the sun provides approximately 1370 Watts per metre of incident energy.
- Burning Coal sucks, but sometimes that's all you've got.
- Human Powered Energy (e.g. riding a bicycle hooked to a generator) may be optimal in terms of energy efficiency (this is a guess), but you'll need a pretty big child-energy generating sweatshop to light up Vegas. People just don't have enough oomph to meet world heat, recreation, and manufacturing needs.
- Nuclear Power Generation holds a lot of promise for the future when we can get to clean fusion, but for now we're stuck with mind-numbingly polluting fission. (and on a tangent, I find it strange that a country with enough fossil fuels to last them for over a hundred years and an stated agenda of wiping out another country feels it needs a nuclear program ASAP)
The list goes on and on. The point is that we should be attempting to optimize the "cleanness" of our energy grid power generation. With multiple hydro generation dams in the grid, excess energy generated via the greener methods can be stored as gravitational potential of water, running it back out to generate more power during peak times. (again, this works just like a huge freakin capacitor in a regulator) In some places around the world, locals can even sell their locally produced energy back into the grid.
I predict that eventually we are going to run into a big power crunch. As in some places already, there will be different electrical power rates for peak and off peak times. I haven't calculated one, but there will be some magic number when it will be economically feasible to cheaply buy grid power in the off-peak time, store it, then sell it back into the grid at the peak time. We're going to reach this point somewhere between when power rates are crazy-high or effective storage systems become incredibly cheap.
When this happens, we will be ready for the most robust power grid in history! When it becomes economically feasible for the buy-store-sell electrical model at the individual level, everybody wins! First, the person buying and selling the grid power makes money doing it (this is the economically feasible part). This person is happy. Second, the power company sells their power to you once at a profit, then makes profit again when they re-sell the power sold back to them at the peak time. They are happy. The power company is especially happy since you have also effectively increased their power storage capacity an incremental amount. When lots of people on the grid start doing this, the result is a huge massively parallel distributed power storage grid. The distributed power storage now in the grid acts like a huge Uninterruptible Power Supply (UPS). If the power goes out, we'll have enough backup capacity for a little while, even if local segments are isolated from the larger grid! I don't see how this is anything except win-win-win for everybody involved.
Wouldn't it be ironic if it were a power shortage and monetary greed that allowed the conditions necessary for society to create a more robust power grid?
Burton MacKenZie www.burtonmackenzie.com
Thursday, May 10, 2007
Last month, Google announced that Stephen Colbert is the Greatest Living American. Later they said he's not. Then this guy declared himself Greatest Living American. If we're just callin' it, then Burton MacKenZie is the Greatest Living American!
Here's some pictures of The Greatest Living American, Burton MacKenZie. The first one is "thoughtful".
This one is "ponderous".
The third is batshit crazy.
Good thing Canada is in the Americas, making me eligible for this title. C'mon, Google, you can do it! I'm counting on you! Burton MacKenZie is the Greatest Living American! Woot! Make a link back to here to vote me in.
Burton MacKenZie www.burtonmackenzie.com
Tuesday, May 08, 2007
Spectrum Analysers are too damn expensive for me, but they are handy for troubleshooting signals. I have found a low tech good-enough-until-further-notice spectral analyser solution for tight band-limited signals: the audio input to some disused linux box!
First, go to baudline.com and get your free copy of baudline. Connect a microphone to the audio jack and you're in business! Start talking and notice the spectral difference between consonants and vowels (consonants have wideband high frequency content). I use it for visual feedback on harmonics on practicing khoomei. (see screenshot below) Note that the frequency snapshot is selected by the white line. The fundamental band of my khoomei attempt starts around 2kHz, and the fifth harmonic is selected somewhere around 9.6kHz (I know it's the fifth because I saw the 2nd through 4th a little earlier). I need a lot more work on harmonic stability!
While watching the spectral content of your voice with baudline is a lot of fun, your voice has limited use in signal troubleshooting/analysis. I'll show you some other ways to use it using the microphone as an accoustically coupled "probe".
On the workbench I keep a radio playing. I like listening to music while I
putter around work hard in the garage. The microphone and baudline easily picked up the roughly 6-7kHz audio broadcast from the radio speakers, but I also wanted to look at the spectrum of the audio signal coming out of my old black and white television, simultaneously. Since my spectral analyser was running on an accoustic link (the microphone), I would normally have to turn off the radio in order to get a cleanly represented television audio spectrum. Normally, that is, if you didn't happen to have a function generator with modulation inputs laying around, too. I plugged a jack from the TV headphone out into the function generator and AM modulated it to 12.5kHz, which I used to drive a small orphaned headphone speaker. The sound from it also filled the air, but with a different bandwidth at different frequecies. In the spectrum below you can see the lowband radio (1 to 7kHz) in the upper left (then they had a dead moment before commercial) and the higher band television audio signal (echoed on each side of the carrier at ~12.5kHz), with lots of empty space between them.
In case you hadn't noticed yet, holy crap look closely at that crazy looking modulated spectrum! It almost looks like there is some Mayan or Aztec-like image encoded into the spectrum, just like in Aphex Twin's own face that he inserted into Windowlicker.
The audio port is digitally sampling at only 48kHz, so its maximum bandwidth is less than 22kHz, the Nyquist Limit. However, the important word is bandwidth, not frequency; The low end of the band does not have to be 0Hz. With a little mathematical magic from baudline, you can take your band-limited signal within a 48kHz window and downsample to a smaller arbitrary frequency window getting increased spectral resolution in the band. In the photo below, I've zoomed in from the range of 0 to ~22kHz. The window now shows 11.8 to 13.2kHz only, at much higher frequency resolution (1.4kHz window). That is the (allegedly) 12.5kHz carrier right in the middle, and now not all the sideband information can fit into this scale.
When I was young and playing with fractals (specifically, the Mandelbrot Set), I could zoom in on the images forever and ever, always wanting to see what the next level of magnification held. So too, it seems, with spectral analyes. I took the downsampling up a notch and got viewing in tight between 12.465 and 12.510kHz (45Hz bandwidth!)
Unfortunately to get this level of resolution, the signal gets averaged over a macroscopic amount of time, and all the signals look blurred together. You can't see any transients. However, you can see that the carrier tone appears to be centred a lot closer to 12490.63kHz than 12.5kHz. I'm not complaining, and I believe that error is less than the error in calibration of the 48kHz sampling rate, anyway.
I love using baudline for looking at real time spectrums. If you had a signal that was sufficiently band-limited (less than 22kHz), you could use a function generator (with modulation input) to demodulate a signal from a much higher frequency into something reproduceable over the accoustic link to the microphone input and still get a reasonable, measurable spectrum. (Don't forget to turn off the radio, too! ;-) Sure, you could just hook up electrically from the function generator into the microphone (or line-in) input if you watch the levels, but where's the fun in that?
Burton MacKenZie www.burtonmackenzie.com